Process of separating impurities from liquids



AW C. H. HAPGOOD 1,711,315

PROCESS OF SEPARATING IMPURITIES FROM LIQUIDS Filed Aug. 24, 1921 lmwroe w/m ass: Cyrus award W00 Jim/Mfr.

Patented Apr. 1929.

UNITED STA,

ES'YPIATENT, OFFICE.

' CYRUS HOWARD HAPGOO I), OE NO'TLEY, NEW JERSEY, ASSIGNORTO THE'DE LAVAL QSEPARATOR COMPANY, OF NEW YORK, Y., A CORPORATION OF NEW JERSEY.

PROCESS OF SEPARATING IMPURITIIES FROM LIQUIDS.

1 Application filed August 24, 1921., Serial No. 495,134.

The utilization of centrifugal force to purify liquids by the elimination therefrom of solids or of other liquids of different specific gravity from that of the liquid to be purified, is well known and has been practiced succesfully in many arts. Where the separation of two liquids is required and those liquids are immiscible with each other, no special problem arises. Where the liquid to be purified is mixed with solids, these latter may be removed either b means of a centrifugal clarifier or by the mtroduction of a heavy cushionin liquidinto a centrifugal separator. Where a clarifier' is used, the solids adhere to the wall of the centrifugal bowl, whose rotation must be arrested at intervals and the solids cleaned out of the bowl by scraping or flushing. In the other process, involving the use of a separator, the heavy cushioning liquid may be present in the original mixture or it may be deliberately added. In either case, if the heavy liquid is of higher specific gravity than the solids, it will carry the solids with it out of the bowl, and even if somewhat lighter than the solids, it may have a sludging action upon the solids that will reduce the frequency which with the bowl must be cleane I When two liquids are in solution, it is obvious that centrifugal force isunavailable to separate them. However, in certain cases, the two liquids can be thrown out of solution by subjecting them to a low temperature. Thus, in the separation of waxes or parafiins from cylinder stock, it has been long well known to dilute the cylinder stock with a light petroleum product, such as naphtha and chill to solidify the waxes. The wax can then be removed by settlement. This is a process that was old and well known lon before the development and perfection o centrifugal machinery. With modern and more nearly perfected separators, the wax can be removed by utilizing a heavy liquid, such as brine, to carry the wax out of the bowl. This latter process is of questionable value, however, because the problem of separating 'the wax from the brine, which is theoretically very simple, is practicallyve diflicult, and inasmuch as the wax'is a valua le product,-no process which fails to secure its economical separation is commercially racticable. Moreover, the above process-,invoves a number of centrifugal operations, as well as contheflow of the wax is necessarily relatively sluggish, with the result that although it flows sufliciently freely to discharge from the bowl,

it clogs the outflow conduits of the stationary receiving pan, which obstructs the discharge from the pan to the wax receptacle and causes a back flow of the wax into the space between the frame and the bowl. This difiiculty, however, I have overcome by subjecting the wax, immediately upon its discharge from the centrifuge, to heat sufficient to change it from a slow flowing semi-solid to a rela tively free flowing liquidl The advantage of the process is that in one centrifugal operation there is a complete separation of the oil from the wax and that the wax is recovered in such condition that its purification presents no technical difliculties. a

In order that my invention may be readil carried out by those skilled in the art, have illustrated a known workable and efficient type of separator together with a special and improved receiving pan which is adapted to be heated and thereby heat the wax dischargedthereinto. V

In the drawings, Fig. 1 shows the upper part of a centrifugal machine, principally in central sectionand more or less diagrams is then fed into the bowl, where, under the.

' influence of centrifugal force, the heavier.

waxes are thrown to the peripher of the bowl, while the lighter oil is disp aced inwardly, the two ingredients being separately discharged into two receiving pans. The receiving pan into which the waxes are discharged, or the delivery tubes leading therefrom or both, are steam j acketed,'so that immediately upon their discharge from the machine, the temperature of the waxes is raised to so reduce their viscosity that they flow freely out of thespouts into the vessel provided for their reception.

Inasmuch as it is desirable, in practicing my process. to use the most efficient type of separator, I have illustrated the same in detail. Itwillbe understood, however, that the practice of the process is not limited to the use of any particular construction of centrifuge nor to any particular means for heating the waxes upon their emergence from the bowl.

a is the bowl body or shell; Z), the central feed tube; 0, conduits leading therefrom to the bottom of the bowl; cl, the bowl liner the discs of which are provided with vertically aligning orifices e in vertical alignment with the discharge mouths of the channels 0; f, the top disc; 9, h, wings compelling the heavy materials near the periphery of the bowl to rotate with the bowl.

' n and 0 are provided.

receives the waxes, the intermediate pan n The heavier waxes are thrown out toward the periphery and escape between the wall of the bowl and the outer edge of the top disc 7, into the space above the top disc, along which they flow and are discharged from the bowl overthe weir i at the top of the bowl neck. The lighter oil is displaced inward and flows up inside the neck of the top disc and is discharged over the weir at the top of such neck. v

A series of stationary receiving pans m, The lower pan m the oil, and the upper pan any overflow from the feed pipe I).

The lower pan m is provided withintegral spouts 7a, which are of limited height but relatively great width. These spouts are steam jacketed, as is the sidewall of the pan m. The steam jacket is shown at 7). The waxes discharged from the bowl at 2' immediately contact with this heated wall and are tl'ierebyraised in temperature sufficiently to render them more free flowing. As they flow through the spouts is, they. are surrounded by a heating medium, so that they outflow freely from the contracted ends of the spouts k.

My invention is also applicable to certain methods of treating wax distillates of petroleum to separate the waxes from the oil. In the case of wax distillates the congealed waxes are crystalline, instead of amorphous as in the case of cylinder stock, and the permissible range of congealing temperature would be from 20 to 35 F., preferably 25.

My invention is of particular value in its application to the treatment of cotton seed and other vegetable oils wherein the oil is treated withan alkali to saponify the fatty acids of the oil and the mixture of oil and soap subjected to centrifugal force to separate the soap from the oil. In this process the flow of soap through and out of the receiving pans is so sluggish that it tends to clog the spouts. By my process the objectionable action is entirely overcome.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is v .1. The process of separating from a liquid a'substance admixed or emulsified therewith and which, while capable of being separated therefrom by centrifugal force, is relatively non-free-flowing, which comprises subjecting the mixture to centrifugal force to effect the separation of said substance, sub'ecting the separated substance to the actiori of a heating medium while maintaining it out of contact therewith, and flowing away the heated substance.

2. The process of separating from a liquid a substance soluble therein at a relatively high temperature and insoluble therein at a relatively low temperature, which comprises reducing the solution to a temperature sufiiciently low to render said substance insoluble in said liquid, separatin said substance from said liquid b cent'ri ugal force, subjecting the separate substance to the action of a heating medium while maintaining it out of contact therewith, and flowing away the heated substance. I

3. The process of separating from a liquid a substance admixed or emulsified therewith and which, while capable of being sep- 7 arated therefrom by centrifugal force, is, relatively non-free-flowing, which comprises subjecting the mixture to centrifugal force, and separately flowing out of the separating chamber the separated constituents, conveying said separated constituents to their ulti- CYRUS HOWARD HAPGOOD. 

